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Tim(at)MyRV10.com
Guest

Posted: Tue Oct 17, 2006 3:59 pm Post subject: engines

We're actually almost up to 650....believe it or not. It's truly

amazing.



Oh, and Dan, man, you're definitely not average....the average guy

ain't nearly as friendly as you.    Can't wait to see y'all

again.



Tim Olson - RV-10 N104CD - Flying

do not archive

RV Builder (Michael Sausen) wrote:

 	  Quote: 	
		     If they aren't targeting the RV market with the 540-X, they really 

 have their heads up their rear-ends!  Considering the RV-10 is probably 

 the single biggest market for the Lyc 540-X with over 600 kit's out 

 there in 3 years, they should be kissing our butts making sure someone 

 doesn't come out with an alternative.  But alas, they would rather stick 

 all of us with the cost of their manufacturing defects of the past and 

 drive us to find other solutions.

  

 Michael Sausen

 -10 #352 Fuselage

 do not archive

 

 ------------------------------------------------------------------------

 *From:* owner-rv10-list-server(at)matronics.com 

 [mailto:owner-rv10-list-server(at)matronics.com] *On Behalf Of 

 *GRANSCOTT(at)aol.com

 *Sent:* Tuesday, October 17, 2006 12:30 PM

 *To:* rv10-list(at)matronics.com

 *Subject:* Re: Re: engines

 

 Our EAA group will be touring the Lycoming factory next week and I can 

 bring up the subject of experimentals for RV 10's if you like...but I'm 

 sure they are not really targeting the RV market rather assuming that we 

 will all just jump on the bandwagon.

  

 Patrick Scott

 EAA 240 Prez

 

 *

 

 href="http://www.matronics.com/Navigator?RV10-List">http://www.matronics.com/Navigator?RV10-List

 

 *

 

 *

 

 

 *

Kellym

Joined: 10 Jan 2006
Posts: 1706
Location: Sun Lakes AZ

Posted: Tue Oct 17, 2006 5:32 pm Post subject: engines

Is #2 demo aircraft an anemic performer? Is only 800-1000fpm an anemic 

climb? There are plenty of certified planes that don't do as well at 

full gross, sporting "only" 200 hp, or less. From the Comanche 180, 

Mooney M20C 180hp, to the Mooney 201 that goes almost as fast as a -10 

on less gas and "only" 200 hp. I don't think it is considered anemic. 

Has a gross wt of 2740 lbs for most versions, with a few that were 

increased to 2900. Not everyone needs to go up at 1500ft a minute. The 

201 has service ceiling around 18000 ft, which most consider adequate 

for a non-turbo aircraft. No, it won't handle the short fields a -10 

will, but as others have said, that depends entirely on your mission 

requirements. Will the IO-540 produce 150hp on under 11gph? I kind of 

doubt it. The IO-360 definitely will and does every day. Will the -10 do 

165kts on that hp? At gross wt?



John W. Cox wrote:

 	  Quote: 	
		  

 A reduction of 260 to 210 is a 19.2% reduction in BHP. To maintain the 

 same robust HP/Weight and not have an anemic performer, then the gross 

 weight would have to be reduced to 2208 pounds.



 For simpletons like me that’s 492 pounds of offloaded fuel or 

 passengers cause there just is not that much difference in powerplant 

 weight saved on the empty weight side of the equation. I guess that 

 means a RV-9 with a four banger. Now where is my math supporting a 

 more anemic engine. Oh, yeh – four cylinders instead of six, Fuel 

 Consumption. Oh, no – I forgot about pulling the throttle back and 

 running a more anemic power output. Thus saving the throttle for the 

 quick go arounds and climbouts to avoid weather.

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

jesse(at)itecusa.org
Guest

Posted: Wed Oct 18, 2006 5:23 am Post subject: engines

Kelly,



On my flight to and from OSH this year we averaged about 10.5gph in cruise

are around 165Kts TAS.  I don't know how many HP we were producing, but I

thought that was somewhat a calculation of MAP, RPM and GPH.  That said, I

would agree that the -10 outclimbs most other planes I have been in, and the

Cessnas I have experienced are pathetic in comparison, so a slower climb

would feel more "normal" rather than "anemic".



Jesse Saint

I-TEC, Inc.

jesse(at)itecusa.org

www.itecusa.org

W: 352-465-4545

C: 352-427-0285



--

AV8ORJWC

Joined: 13 Jul 2006
Posts: 1149
Location: Aurora, Oregon "Home of VANS"

Posted: Wed Oct 18, 2006 7:49 am Post subject: engines

Let me respond right here that the disgusting phrase "Hot Rodding" that

I have used in the past is a tongue in cheek mumble that VAN regularly

uses and for the benefit of Ken Scott who lurks on this list and tattles

on all who modify this great aircraft.  I have a lot of respect for

Randy who built a "By the book, no deviation allowed" RV-10.  However, I

encourage and support those who modify this great basic entry cruiser

aircraft into what it deserves to become. The most prolific and popular

4 place kit built aircraft on the planet. I am a proponent of

multi-screen glass efis, higher compression pistons, improved induction,

improved cooling, improved exhaust, improved cowling, improved braking,

improved aesthetics, improved graphics and improved composite work.  The

phrase that builders would fall out of the sky or suffer catastrophic

control flutter by making such logical improvements was from the editor

of the RVator.  I don't buy it, I have the same passion that VAN did

when he Hot Rodded the Playboy into his first RV.



I have 283 ideas (and growing) for improving this great design. Many of

those are being incorporated with aircraft builders willing to move off

the "plans only" construction concept. Don't get me wrong, I respect

those of you who do not deviate. I though, am waiting for a resolution

of the 51% rule before moving ahead with my plans for Builder Assist -

Commercially.  I think that Tim, Scott and Deems are doing a great job

of growing the spirit of the Home Building Community on this post and on

their websites. It is with tremendous thrill and pride that I

acknowledge I am but a small part of this 650 kits sold, 55 kits flying

and lurker community.  They just keep getting better and better.  I wish

more was done at VANS to improve the quality, update the publication and

speed the boxing and shipping process. If Ken Krueger comes to our

dinner Friday, this will be a point worth sharing.



I am praying that Scott flies to Casa Grande next weekend so he can fly

home with Grand Champion - Copperstate. I will help reimburse him for

fuel if he does so. Ray, Scott and Ranae deserve it.  The rest you need

to at least view their pictures.  At 10 mega pixels he did not scrimp on

the quality.  Not on his motorcycle, his hangar, his bicycle, his

partnership or that fabulous aircraft.  Congrats again Ray for providing

Scott's continuity and to Ranae's patience.



Where is James McClow to share in all this excitement?



John #600



--

james.k.hovis(at)gmail.co
Guest

Posted: Wed Oct 18, 2006 8:45 am Post subject: engines

Flutter and dynamic divergence are REAL issues every airframe designer (and for that matter, pilot) has to deal with especially so for higher-performance aircraft. There are two ways to set Vne in FAR Part 23. One, do ground vibration tests to find resonant frequencies (mainly shake the crap out of it and see if anything falls off) of the airframe, then go out and flight test to find its flutter point, then set the Vne at few per cent below this speed. The other is to use the canned Vne minimum speed formula based on wing loading. The canned formula is based on statistics from certified aircraft that if you set Vne at this speed or below, you won't encounter flutter. I suspect Van's took the conservative approach and set Vne based on the canned formula. Now as Van points out, weight affects flutter. Balance of control surfaces affect flutter (see Steve Whitman's crash several years ago), and horsepower available affects flutter. Most low-power spam-cans don't have the power to ever approach Vne except in steep dives, while adding power means the top speed capable (that point where the power available curve crosses the power required for level flight curve) creeps ever closer to the flutter point. Now, don't get me wrong, if someone want to drop in a 300hp engine into an RV, they are more than welcome to do it. However, they should get a professional test pilot to verify the Vne and flutter point for the configuration or get training on how to react when flutter happens (the time from flutter onset to complete divergence can be REAL small). Understanding the full ramifications of modifications to the original design and testing for it may save someone's life in the end.  

  

 JKH 



 

 On 10/18/06, John W. Cox <johnwcox(at)pacificnw.com (johnwcox(at)pacificnw.com)> wrote: [quote]--> RV10-List message posted by: "John W. Cox" <johnwcox(at)pacificnw.com  (johnwcox(at)pacificnw.com)>



Let me respond right here that the disgusting phrase "Hot Rodding" that

I have used in the past is a tongue in cheek mumble that VAN regularly

uses and for the benefit of Ken Scott who lurks on this list and tattles 

on all who modify this great aircraft.  I have a lot of respect for

Randy who built a "By the book, no deviation allowed" RV-10.  However, I

encourage and support those who modify this great basic entry cruiser 

aircraft into what it deserves to become. The most prolific and popular

4 place kit built aircraft on the planet. I am a proponent of

multi-screen glass efis, higher compression pistons, improved induction,

improved cooling, improved exhaust, improved cowling, improved braking, 

improved aesthetics, improved graphics and improved composite work.  The

phrase that builders would fall out of the sky or suffer catastrophic

control flutter by making such logical improvements was from the editor 

of the RVator.  I don't buy it, I have the same passion that VAN did

when he Hot Rodded the Playboy into his first RV.



I have 283 ideas (and growing) for improving this great design. Many of

those are being incorporated with aircraft builders willing to move off 

the "plans only" construction concept. Don't get me wrong, I respect

those of you who do not deviate. I though, am waiting for a resolution

of the 51% rule before moving ahead with my plans for Builder Assist - 

Commercially.  I think that Tim, Scott and Deems are doing a great job

of growing the spirit of the Home Building Community on this post and on

their websites. It is with tremendous thrill and pride that I

acknowledge I am but a small part of this 650 kits sold, 55 kits flying 

and lurker community.  They just keep getting better and better.  I wish

more was done at VANS to improve the quality, update the publication and

speed the boxing and shipping process. If Ken Krueger comes to our 

dinner Friday, this will be a point worth sharing.



I am praying that Scott flies to Casa Grande next weekend so he can fly

home with Grand Champion - Copperstate. I will help reimburse him for

fuel if he does so. Ray, Scott and Ranae deserve it.  The rest you need 

to at least view their pictures.  At 10 mega pixels he did not scrimp on

the quality.  Not on his motorcycle, his hangar, his bicycle, his

partnership or that fabulous aircraft.  Congrats again Ray for providing 

Scott's continuity and to Ranae's patience.



Where is James McClow to share in all this excitement?



John #600



--

John Ackerman

Joined: 19 Jun 2006
Posts: 130
Location: Prescott, AZ

Posted: Wed Oct 18, 2006 9:18 am Post subject: engines

 	  Quote: 	
		    The easiest way to get economy is to fly higher (to a point), and

 go LOP on the mixture.


	


OK — flamesuit on —

Respectfully disagree. Somebody from Embry-Riddle Florida once (4-5 

years ago?) posted a cogent argument that still air range is pretty 

much independent of altitude and dependent only on power setting. I've 

lost the reference, but I did a crude thermodynamic analysis and sure 

enough, got the same result. I'm way too lazy to repeat the analysis 

unless forced.



What altitude gets you is more speed at the same range.



John Ackerman

jesse(at)itecusa.org
Guest

Posted: Wed Oct 18, 2006 9:46 am Post subject: engines

I don't know about thermodynamic analysis and all that, but when we go high,

we go further on a tank of gas.  Maybe it is just the issue of being able to

more safely go LOP on the mixture, which obviously makes some difference,

which you can't/shouldn't do at high power settings.  I would have to stank

with whoever you quoted on this one, based on experience.  But, I don't use

experience to establish truth, just to illustrate it, so I could certainly

be wrong based on my experience.



Do not archive.



Jesse Saint

I-TEC, Inc.

jesse(at)itecusa.org

www.itecusa.org

W: 352-465-4545

C: 352-427-0285



--

owl40188(at)yahoo.com
Guest

Posted: Wed Oct 18, 2006 1:24 pm Post subject: engines

John,

  

 I think Jesse is correct.  You get a longer range at altitude.  Look at it this way, if your true speed increases with altitude the only way your range could stay the same is if you are burning more fuel for the same power setting.  I don't think thats the case.  Range and speed both increase because the total drag is a bit less due to the less dense air.

 

 

Niko 

40188 



 ---

jdalton77(at)comcast.net
Guest

Posted: Wed Oct 18, 2006 3:07 pm Post subject: engines

I'm adding a small hat-shelf behind the  baggage compartment for jackets, maps, etc, and other 'light but bulky"  luggage.  

  

 Will my -10 fall out of the sky?  If I placard  it will it be OK?

  

 Don't miss the sarcasm.

  

 Jeff

 [quote]   ---

AV8ORJWC

Joined: 13 Jul 2006
Posts: 1149
Location: Aurora, Oregon "Home of VANS"

Posted: Wed Oct 18, 2006 6:18 pm Post subject: engines

Thanks James for opening the can of worms.  RV-10s deserve the same design criteria and flight potential as Lancairs (some run 310 or 350 hp powerplants).  Builders should know why those RV-10 speeds are as slow as they are.  And yes, I love the stall speed. You have now correctly posted why the patch repair to a control surface should not be attempted as some discussion here allowed just a few days ago.  Buy a new skin and repair it to original spec.  Flutter at under 200 knots could be easily designed out of the RV-10.  Is this why the HP is factory limited at 260.00?  Could there actually be compelling reasons for never ever considering a TNIO engine?  These have been reasonable questions which are Verboten, cause they address both modification and oh dear, hot rodding. Is someone implying that there are no areas for ease of improvement such as CNC engineered components or improved composite attachments?  

   

I think the spirit of improvement, enhanced safety and expanded public knowledge are alive and well here.  

   

Oh yeh, and I also espouse balancing of All painted and moveable control surfaces and the instructions for how to do so for every single kit builder.  For the conservative at heart, I applaud “No deviation or modification – included in this aircraft”.  

   

I think the RV-10 has the ability to safely operate as a High Performance aircraft in the hands of a proficient pilot and provide decades of satisfying recreational activity to the pilot and passengers.  

   

JWC  

Do not Archive  

         

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of James K Hovis

 Sent: Wednesday, October 18, 2006 9:43 AM

 To: rv10-list(at)matronics.com

 Subject: Re: Re: engines  

  

     

Flutter and dynamic divergence are REAL issues every airframe designer (and for that matter, pilot) has to deal with especially so for higher-performance aircraft. There are two ways to set Vne in FAR Part 23. One, do ground vibration tests to find resonant frequencies (mainly shake the crap out of it and see if anything falls off) of the airframe, then go out and flight test to find its flutter point, then set the Vne at few per cent below this speed. The other is to use the canned Vne minimum speed formula based on wing loading. The canned formula is based on statistics from certified aircraft that if you set Vne at this speed or below, you won't encounter flutter. I suspect Van's took the conservative approach and set Vne based on the canned formula. Now as Van points out, weight affects flutter. Balance of control surfaces affect flutter (see Steve Whitman's crash several years ago), and horsepower available affects flutter. Most low-power spam-cans don't have the power to ever approach Vne except in steep dives, while adding power means the top speed capable (that point where the power available curve crosses the power required for level flight curve) creeps ever closer to the flutter point. Now, don't get me wrong, if someone want to drop in a 300hp engine into an RV, they are more than welcome to do it. However, they should get a professional test pilot to verify the Vne and flutter point for the configuration or get training on how to react when flutter happens (the time from flutter onset to complete divergence can be REAL small). Understanding the full ramifications of modifications to the original design and testing for it may save someone's life in the end.    

    

   

    

JKH 

 

    

    

On 10/18/06, John W. Cox <johnwcox(at)pacificnw.com (johnwcox(at)pacificnw.com)> wrote:   

  [quote]--> RV10-List message posted by: "John W. Cox" <johnwcox(at)pacificnw.com >



Let me respond right here that the disgusting phrase "Hot Rodding" that

I have used in the past is a tongue in cheek mumble that VAN regularly

uses and for the benefit of Ken Scott who lurks on this list and tattles 

on all who modify this great aircraft.  I have a lot of respect for

Randy who built a "By the book, no deviation allowed" RV-10.  However, I

encourage and support those who modify this great basic entry cruiser 

aircraft into what it deserves to become. The most prolific and popular

4 place kit built aircraft on the planet. I am a proponent of

multi-screen glass efis, higher compression pistons, improved induction,

improved cooling, improved exhaust, improved cowling, improved braking, 

improved aesthetics, improved graphics and improved composite work.  The

phrase that builders would fall out of the sky or suffer catastrophic

control flutter by making such logical improvements was from the editor 

of the RVator.  I don't buy it, I have the same passion that VAN did

when he Hot Rodded the Playboy into his first RV.



I have 283 ideas (and growing) for improving this great design. Many of

those are being incorporated with aircraft builders willing to move off 

the "plans only" construction concept. Don't get me wrong, I respect

those of you who do not deviate. I though, am waiting for a resolution

of the 51% rule before moving ahead with my plans for Builder Assist - 

Commercially.  I think that Tim, Scott and Deems are doing a great job

of growing the spirit of the Home Building Community on this post and on

their websites. It is with tremendous thrill and pride that I

acknowledge I am but a small part of this 650 kits sold, 55 kits flying 

and lurker community.  They just keep getting better and better.  I wish

more was done at VANS to improve the quality, update the publication and

speed the boxing and shipping process. If Ken Krueger comes to our 

dinner Friday, this will be a point worth sharing.



I am praying that Scott flies to Casa Grande next weekend so he can fly

home with Grand Champion - Copperstate. I will help reimburse him for

fuel if he does so. Ray, Scott and Ranae deserve it.  The rest you need 

to at least view their pictures.  At 10 mega pixels he did not scrimp on

the quality.  Not on his motorcycle, his hangar, his bicycle, his

partnership or that fabulous aircraft.  Congrats again Ray for providing 

Scott's continuity and to Ranae's patience.



Where is James McClow to share in all this excitement?



John #600

 [b]

wv4i(at)bellsouth.net
Guest

Posted: Thu Oct 19, 2006 3:19 am Post subject: engines

Not likely, unless you're already near your aft CG limit already, or 

some other unrelated factor comes into play. But, you should compute 

operating weight CG for each and every flight, including at takeoff and 

predicted landing fuel loads. And, you should determine, somehow, the 

mean fuselage station for extra compartments such as you describe, and 

the weight at such station. The Garmin GPS x96 series have an excellent 

weight and balance capability for such a computation that takes seconds 

to compute.



I have a neighbor that once owned an RV-6, and just could not get the 

landings down. Enter another neighbor, high time experimental driver and 

tail dragger type (and also ex F16/F4 driver) and he could not get it 

either. Go to weigh the airplane and it's 70+ pounds at the tail while 

my RV6 is 52. That's a BIG difference in moment-arm for just 18 lbs, 

because it's so far away fm the 0 station, if you will. Go figure. Your 

extra compartment is a great idea, but it also has the longest arm of 

any station where the weight varies. The 70+ lb tail was not reflected 

in the prior owner's Wt & Bal computations, EOW CG to be exact. Did 

somebody just decide to make the tail somehow heavier, beefier, etc.? 

Who knows? Nothing was obvious. The point is that with experimentals, 

the FAA has given the owner or builder much more latitude to hang 

themselves. This discussion applies to any mods that deviate fm the kit 

manufacturer's plans.



I'm not without sense of humor, or ability to be sarcastic, to say the 

least, but I also appreciate the apparent background and knowledge of 

many of the posters to this type forums. I've been flying professionally 

since 1979, and at this point I'm really into experimental flying for 

education and enjoyment. Others?



Link McGarity

#40622 elevator

GRANSCOTT(at)aol.com
Guest

Posted: Thu Oct 19, 2006 4:43 am Post subject: engines

Niko you'll get 10-40% more range depending upon altitude, additionally  with less oxygen you cannot burn as much fuel at altitude so your power goes  down but you're moving faster because the air is "thinner"...if you could get to  up upper levels it gets even better.  That's why jets use a lot of fuel  getting to altitude but use very little fuel at altitude.  

  

 To get to higher altitudes you need one of several engine types:   rocket, jet or turbo/turbine types.  With normal aspiration you can  only get so high before you run our of "air".  Mooney created a sort of  mini charge at one time by a small recirculation unit that would give you about  an other 1"+ of boost on MP.   Maybe Kelly could tell us how they did  this and if one could use that in an experimental engine to give you a little  more boost with out the need for a tubro, waste gate, fans etc.

  

 Patrick

  [quote][b]

Kellym

Joined: 10 Jan 2006
Posts: 1706
Location: Sun Lakes AZ

Posted: Thu Oct 19, 2006 5:01 am Post subject: engines

Sorry to disappoint you, but Mooney's "Ram Air" was nothing more than a 

bypass of the airfilter, and was better located than the air filter to 

get straight-through flow into the fuel injection servo. Mooney's 

standard filter location was on a low pressure area at the bottom of the 

cowl, where the ram air inlet was on the front right behind the prop. 

Lopresti did it a bit better, extending the inlet out to be closer to 

the prop blade in optimized location to get a bit of "compression" from 

the prop.

You aren't going to do better than atmospheric without going to a turbo 

or supercharger.

Everything else is just improving the physics of getting atmospheric 

into the engine.

GRANSCOTT(at)aol.com wrote:

 	  Quote: 	
		   To get to higher altitudes you need one of several engine types: 

  rocket, jet or turbo/turbine types.  With normal aspiration you can 

 only get so high before you run our of "air".  Mooney created a sort 

 of mini charge at one time by a small recirculation unit that would 

 give you about an other 1"+ of boost on MP.   Maybe Kelly could tell 

 us how they did this and if one could use that in an experimental 

 engine to give you a little more boost with out the need for a tubro, 

 waste gate, fans etc.

  

 Patrick

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

bhughes(at)qnsi.net
Guest

Posted: Thu Oct 19, 2006 5:34 am Post subject: engines

This is the data for airspeed vs pressure increase. Assuming the perfect

setup. 



Knots Inches of Mercury

60   0.1727

80   0.3075

100   0.4814

110   0.5832

120   0.6950

130   0.8168

140   0.9488

150   1.0910

175   1.4918

200   1.9589

225   2.4943



Ram air can help. 



Bobby 

40116

 



--

GRANSCOTT(at)aol.com
Guest

Posted: Thu Oct 19, 2006 6:38 am Post subject: engines

Thanks, Kelly...enjoy the rest of your trip...

  

 P

  [quote][b]

owl40188(at)yahoo.com
Guest

Posted: Thu Oct 19, 2006 2:02 pm Post subject: engines

Well I just looked at the Cessna 172 S POH

    for standard day

  

 at 2000 ft  73% BHP 9.9 gph   115 KTAS

 at 4000 ft  73% BHP 9.9 gph   117 KTAS

 at 6000 ft  73% BHP 9.9 gph   119 KTAS

  

 For the same fuel flow at higher altitude you get a higher speed thus a longer range.

  

 This is clearly depicted in the range curve of the 172s POH (Figure 5-9).

  

 at 55% power

 at sea level   585 miles  101 KTAS

 at 120000 ft 605 miles   110 KTAS

  

 I think part of the problem with the many of the academic articles is that they are trying to calculate maximum range irregardless of what power an engine can operate at.  If you set power to a certain level as 70% than the higher altitude will get you a better range.  Obviously this does not acount for fuel burn to clim.

 

Niko  



 ---

John Ackerman

Joined: 19 Jun 2006
Posts: 130
Location: Prescott, AZ

Posted: Thu Oct 19, 2006 6:56 pm Post subject: engines

Niko, here's the deal as I see it:



	For maximum range, the airplane must be flown at the airspeed/AOA for 

minimum drag. That speed increases with altitude, although the minimum 

drag remains pretty much constant. The minimum power required increases 

directly with the speed, i.e. power equals speed times drag. The speed 

vs. altitude data you present below are at _constant_power_, and for 

that condition, you are certainly correct. The reason for the speed 

increase is that at the higher altitudes, the speed more closely 

approximates the speed for minimum drag.



	Constant power is not the maximum range condition, though. For maximum 

range, the power is really low for most prop/recip aircraft – well 

below 50% at lower altitudes – and it increases with altitude at the 

same rate that the speed does - hence constant max range with altitude. 

Again, the range numbers presented below reflect the fact that at 

higher altitude the plane is being operated closer to the ideal 

AOA/airspeed for minimum drag.



	Yep, it takes energy (fuel) to climb to altitude, but if you fly 

right, you get it back when you descend.



	There's a really good reason for flying higher if you want range - 

many of us are range limited by our physiological needs, and at 

altitude you get the same miles/gallon and range, but at a higher 

speed, so you can go farther before your body (or your passenger's 

body) dictates a landing.



All this stuff assumes constant engine efficiency. That approximation 

is way better than the errors induced by my stick skills - maybe even 

most folks' skills. It also assumes still air, but that's another story 

entirely.



Best wishes,

John Ackerman

On Oct 19, 2006, at 2:58 PM, Nikolaos Napoli wrote:



[quote] Well I just looked at the Cessna 172 S POH

 for standard day

  

 at 2000 ft  73% BHP 9.9 gph   115 KTAS

 at 4000 ft  73% BHP 9.9 gph   117 KTAS

 at 6000 ft  73% BHP 9.9 gph   119 KTAS

  

 For the same fuel flow at higher altitude you get a higher speed thus 

 a longer range.

  

 This is clearly depicted in the range curve of the 172s POH (Figure 

 5-9).

  

 at 55% power

 at sea level   585 miles  101 KTAS

 at 120000 ft 605 miles   110 KTAS

  

 I think part of the problem with the many of the academic articles is 

 that they are trying to calculate maximum range irregardless of what 

 power an engine can operate at.  If you set power to a certain level 

 as 70% than the higher altitude will get you a better 

 range.  Obviously this does not acount for fuel burn to clim.

  

 Niko

 ---

owl40188(at)yahoo.com
Guest

Posted: Fri Oct 20, 2006 6:22 am Post subject: engines

Hi John

  

 I do in general agree with you thats why I made the statement

  "I think part of the problem with the many of the academic articles is  that they are trying to calculate maximum range irregardless of what  power an engine can operate at."

 

  

An engine has to operate at probably the 20% to 40% power range at low altitude to get equivalent range, which I believe is not advisable with our current crop of engines.  Partly due too low engine temperatures and partly due to there not being enough fuel to get a good even fuel./ air mixture for efficient combustion.  So from a practical point of view, for maximum range, you set the minimum power thats advisable to operate the engine at which in turn sets your fuel burn.  So in the RV10 case I believe that for max range your power setting turns out to be the same for all altitudes which is say around 45 to 50%.  At that point you have to climb to get better range. 

  

The article in the link is interesting and I have read several similar articles in the past as this question had preplexed me for a while.  They all reached the same conclusion because they are not accounting for the specific operating requirements of the engines. 



Best regards and thanks for your input  as I don't fully understand all this. 

 Niko 



 ---

Billy

Joined: 17 Oct 2006
Posts: 1

Posted: Fri Oct 20, 2006 11:32 am Post subject: Re: engines

Hello again,



I am the guy who started this subject about a week ago.  Thank you all for participating.  I am still undecided at this point about the engine but your comments have been helpful.



I trained as an A&P in the early 80s, worked for the airlines a while as a mechanic (which does little for you O540 knowledge or generally sheet metal as well). I currently fly for a small cargo airline using the 747-400s, which gets a bit boring on 14 hour flights. 



 I did overhaul a cont. O300 and a lyc O235 back when I was learning to fly.  They seemed to run pretty much the same before and after overhaul.....Have previously owned two older 172s one with the O300 and one with the O320. I cant remember the O300 being that much smoother (could very well just be my memory) Also a 150 a 152 a 210A and a 1976 182



 Would like to connect with other 10 builders in the chicago area.  I have a tail kit and am pretty much done with section 9 and hope to start on section 10 before the end of the year.



One of the posted that struck a cord with me was from Scott  Schmidt:



"Here is the truth with all of this, none of it really matters a lot. 

They all seem like big decisions when you are planning and building but 

when you are flying all you really care about is that the engine runs 

great, you have good communication, and the weather is good. I spent 

days and days (maybe months or a year) planning my panel, paint, wiring 

and interior. When you take off it is nice to have some of the features 

but really you are looking outside and having a great time." 



Thanks Scott.

But thanks to all that have posted.

Billy Kehmeier

kit #574

starting on tail cone

Chicago

millstees(at)ameritech.ne
Guest

Posted: Fri Oct 20, 2006 7:37 pm Post subject: engines

Billy:



I am building a -10 in Naperville. I am using an Eggenfellner Subaru H-6

engine. Give me a call (630) 308-7476 cell



Steve Mills

RV-10 40486 Slow-build

Naperville, Illinois

finishing fuselage

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